Only weeks ago, rebel forces appeared a ragged bunch whose fight to oust longtime dictator Muammar Qaddafi had stalled. In the US, some critics were complaining that the White House appeared to have involved the nation in another endless conflict. Others were taking the opposite position, pushing for more forceful American intervention.

Now the lightly armed rebel fighters, supported by NATO air power, have seized control of most of Libya and are swarming into Tripoli. It’s evident they’re winning, said President Obama Monday from his vacation haven of Martha's Vineyard.

Some Republicans continue to press the point that US forces should have been in the lead on Libya airstrikes, as opposed to serving as part of an overall NATO coalition.

“I grieve a bit because this conflict didn’t have to last this long,” said Sen. John McCain (R) of Arizona on Sunday during an interview on CBS. “United States air could have shortened this conflict, and, unfortunately, we chose not to [employ the full weight of the US Air Force]. We led from behind.”

Moreover, Washington experts are warning that the administration and its NATO allies should not engage in a “mission accomplished” moment of high-fives and then turn their attention to other subjects.

After all, the bitter lesson of Iraq points out that in regime-change situations, sometimes the hardest and most dangerous work occurs after the initial triumph.

Democracy is not magic, Mr. Cordesman pointed out. The US needs to be prepared for the likelihood that elections in Libya trigger deep political divisions and produce winners with little governing experience. Economic reform could struggle to produce jobs for the young, fast-growing Libyan population.

“The most we can do is to foster a climate where we can help them help themselves,” said Cordesman.

That would probably entail financial aid. But given the current economic straits of both the US and its European allies, aid to Libya might be a very difficult thing to sell to domestic voters.

As for the Republicans running to replace Obama, the success of Libya’s rebels presents something of a political problem.

Front-runner Mitt Romney, like 2008 candidate Senator McCain, has criticized Obama for not doing more. His task will be to cheer the downfall of longtime US nemesis Qaddafi, while continuing to promote the idea that it could have happened sooner with a more forceful application of American firepower.

Michele Bachmann, Ron Paul, and Jon Huntsman have all taken the opposite view: that the US had no strategic interests in Libya and should not be wasting time and treasure helping the rebels.

Representative Paul, who opposes virtually all US military intervention abroad, is unlikely to change his views in this instance. His supporters expect no less.

Representative Bachmann is in a trickier spot. While she has said the US has no business in Libya, she has also charged that the rebels contain some supporters of Al Qaeda. She could continue to warn against the dangers of rising Islamism, while celebrating the demise of an American adversary.